The Orla expander offers the following:
3 polyphonic sections, Solo section, Bass section. 30 rhythms with 2 variations, melody / chord sequencer, programmable arrangements, digital reverb, midi in / out / through and stereo outputs,

For the solo section which is played in monophonic mode it is possible to combine monophonic and polyphonic settings to play chords with the right hand with the highest note as monophonic but missed from the polyphonic sequence.  The glide setting can also be applied using an optional pedal.

There are polyphonic presets, polyphonic chorus, polyphonic sustain (variable amount).

With OMC when you play a chord with the left hand a complete chord is added to the right hand (this is a fabulous effect which enables the simulation of multi players from one instrument - my favourite feature).  This setting can be used for close harmony or open harmony configuration. With polyphonic 1, polyphonic 2.

You can also play using the duet setting which adds a second note to the right hand.

Polyphonic 2 presets give further sounds.

Polyphonic chorus gives a fuller sound.

Polyphonic 2 sustain can be set at varying levels.

DCS allows a second polyphonic sound to the chord section.

There are a number of sounds available as bass presets.

Bass sustain is available with varying levels.

Pedal sustain can be assigned to optional pedals.

Fade allows sounds to fade out.

A digital reverb is also available.

The rhythm section includes start / stop, auto start, intro / ending, fill in ½, drum kit, tempo, track 1, track2, auto bass, auto chord, memory, left volume.

Transpose, pitch, octave settings are also available.

This is a summary of some of the main features of the Orla expander which gives thousands of combinations and was built especially for the accordion.  We find it gives a very full sound and we love the musette settings, the automatic harmony additions and especially the spacious sounds.  We also find this unit very easy to use and yet all sections are easily controllable.